The mount is the most common position found in street fights and is the most devastating position to be in. From the top you have the ability to land powerful strikes using gravity to help you deliver incredible power.
Joint locks and chokes can also be easily applied from this position.
If you find yourself on the bottom you obviously need a quick and effective means of escape.
You should practice maintaining and escaping the mounted position until it becomes second nature. In a street fight, a moments hesitation can be very costly. When in the mount you should be totally relaxed but aware of what your opponent is trying to do to land strikes, apply submission holds or escape.
This is the common form of the mount, simply resting all your weight on your opponents stomach or chest. If they attempt strikes, chokes, or other submission holds, you can easily sit back to counter their techniques.
This slight variation shows how to smother your opponent making it difficult for them to breath. They will be tired anyway from trying to escape, this will just frustrate them further. It's also a good position to adopt if you need a rest yourself. Note the position of the hands, this establishes a good base so it is difficult for your opponent to try and roll you off.
In this variation you can wrap an arm round the back of your opponents neck to stop them moving out from underneath you.
If your opponent raises their knees it is sometimes a good idea to 'grapevine' them. This makes it much more difficult to escape from. The usual escape from the mount requires the person on the bottom to raise their hips to roll their opponent off. With both legs wrapped up the person on top can prevent themselves from rolling off.